Light diffusion boxes, also known as "softboxes" have long been used by photographers and camera crews to provide diffused lighting on photographic subjects. Softboxes are especially useful for location shooting, because they are generally light-weight and portable. They are generally made collapsible into compact bundles by using flexible material, such as cloth, which has been stretched on a light-weight framework. Their use for location filming of news events by camera crews makes easy and rapid assembly very important. In an environment where several news crews may be competing for coverage of an event, or where an unexpected occurrence makes response time crucial, every second can be valuable to field journalists. The time spent in assembling lighting equipment for the shooting can make the difference in effectiveness and competitive edge.
Unfortunately, prior art softboxes can be clumsy to assemble and often require a large degree of physical strength. The typical softbox has a flexible framework which supports and gives shape to a fabric housing which surrounds a light source. The light source generally must be very bright, from 150-500 watts, and thus also produces a great deal of heat. Safety considerations therefore dictate that the fabric housing be kept well away from the light source, and not allowed to sag toward it. The supporting structure necessarily stretches the fabric tautly, keeping it under tension. The support structure, in collapsible softboxes, is typically composed of rods which are flexible along some portion of their length, and which are captured within seams or channels formed in the fabric housing. The rods are generally inserted into the channels, which extend to the four corners of the fabric, and then the free ends are inserted into sockets around the circumference of a rigid central hub. The insertion sockets are generally straight channels formed into the corners of the hub, into which the free end of the rod is guided. This often requires that the rod be inserted from a very small range of approach angles, in order to get the parts to mate properly. The insertion can be difficult, as it involves applying pressure to force the flexible rods to bend at the same time that the free end is sought to be inserted in the socket in the central hub. This can require a great degree of physical strength, as well as much patience since the flexible rods are generally not designed to be very easily bent, rather to the contrary, because they must exert tension on the fabric housing to insure that it will not sag.
Additionally, the free ends of the support rods sometimes have no sort of cap structure to blunt the edges of the rod end. There is thus possibility of injury, if one of the rods slips while the user is seeking to align it with its insertion socket. If this springy rod with an unblunted edge snaps out straight, this can cause damage to hands, wrists or eyes as the rod can be expected to straighten with considerable force.
U.S. Pat. No. 4,446,506 to Larson discloses a photographic light diffuser with supporting rods which are placed in metal grommeted apertures in the corners of panel segments. Assembly is done by first attaching the outer-most corners, and then attaching the inner-most corners to extending bolts.
U.S. Pat. No. 4,669,031 to Regester illustrates a light box for photographic use having flexible rods which are inserted into corner loops of the side walls of the housing, forcing them to expand into roughly a truncated pyramidal shape. At the large end of the housing, each loop is closed to prevent the rod ends from passing through. This configuration leads to exactly the disadvantages in terms of convenience and safety which are discussed above.
U.S. Pat. No. 5,023,756, also to Regester, shows a light diffusion box with supporting rods which are apparently inserted into the corner edges of a fabric housing, and then connected at the rod's free ends to a central ring structure. As in the previous Regester patent, this configuration has the precise defects which are enumerated above, and which are addressed in the present invention. In addition, the multi-part rods used have ends which are not interchangeable, which slows assembly.
There is thus a need for an improved light diffusing box which is collapsible, and which assembles and disassembles in a rapid, easy and safe manner.